GT3 gear ratios

Author
Discussion

fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
all the talk earlier of gearboxes coupled with an inability to sleep (not because of gearbox talk) had me dig out my gear ratio charts and quickly calculate some more info for various gear ratios in the GT3 models to see how they shaped up in comparison with each other and the ratios in my 996 Cup.
i just calculated speeds in mph at 7000rpm and rounded to nearest mph, firstly to allow a direct comparison without varying redlines fogging things and secondly because i already had gear charts for most of the cars showing speeds at 7000rpm. its just to allow a comparo, not see who can go the fastest wink

for those of you of a nerdy disposition, enjoy!!! for everyone else, theres plenty other threads smile

03-05 996 Cup:..........1st-45mph,..2nd-70mph,..3rd-96mph,....4th-106mph,..5th-127mph,..6th-153mph
996.1GT3:.................1st-41mph,..2nd-73mph,..3rd-101mph,..4th-130mph,..5th-162mph,..6th-192mph
996.2GT3&RS:...........1st-41mph,..2nd-73mph,..3rd-101mph,..4th-130mph,..5th-157mph,..6th-184mph
997.1GT3&RS&.2GT3:..1st-42mph,..2nd-70mph,..3rd-97mph,....4th-123mph,..5th-150mph,..6th-172mph
997.2 GT3RS:............1st-37mph,..2nd-63mph,..3rd-87mph,....4th-111mph,..5th-135mph,..6th-162mph
2008 997 Cup...........1st-43mph,..2nd-65mph,..3rd-81mph,....4th-99mph,....5th-122mph,..6th-149mph

heres what this means in terms of shifting in the 997 cup. in combination with that engine the cars is always cooking. this highlights the benefits of the short ratios. the next gear doesnt see you drop significant rpm.




Edited by fioran0 on Sunday 19th February 00:04

fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
and for interest:
996 C2.....................1st-39mph,..2nd-68mph,..3rd-99mph,....4th-123mph,..5th-146mph,..6th-178mph
996 Turbo/GT2..........1st-41mph,..2nd-77mph,..3rd-112mph,..4th-141mph,..5th-171mph,..6th-210mph

keep it lit

3,388 posts

167 months

Saturday 18th February 2012
quotequote all

how about a 6.1 ratios with a 8:32 c&p then mate...










off topic.... summer is coming!


Harris_I

3,228 posts

259 months

Saturday 18th February 2012
quotequote all
Thanks for this!

Would the 6.2 with 8:32 c&p be the same as a Cup?

sportsandclassic

3,774 posts

218 months

Saturday 18th February 2012
quotequote all
Harris_I said:
Thanks for this!

Would the 6.2 with 8:32 c&p be the same as a Cup?
Cup cars use an 8.32 ring gear an pinion but I also know there is a 7.35 ring gear and pinion. Never seen one before.


fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
the 8/32 (4.0) final drive change is applied as a percentage drop to each gear so has the effect of very slightly closing the gear spacing as larger speeds are reduced more than lower ones. it mainly just lowers the speed across the board though. the cup has completely different ratios fitted to keep the spacing shorter between gears.
with an 8/32 fitted you get:
6.1GT3......1st-34mph,...2nd-63mph,...3rd-83mph,...4th-106mph,...5th-133mph,...6th-157mph
6.2GT3......1st-34mph,...2nd-63mph,...3rd-83mph,...4th-106mph,...5th-130mph,...6th-152mph

changing to an 8/32 on the street boxes helps shorten things down so that 4,5 and 6 can be brought into use easier but at the expense of a much shortened 1,2 and 3.

Edited by fioran0 on Saturday 18th February 11:26

nxi20

778 posts

205 months

Saturday 18th February 2012
quotequote all
sportsandclassic said:
Cup cars use an 8.32 ring gear an pinion but I also know there is a 7.35 ring gear and pinion. Never seen one before.
The 7:35 ratio is designed for sprints & hillclimbs AIUI. Has a life measured in hours, I'm told.

fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
the 7/35 R&P was for the GT3R/RS though can be fitted in the Cups however not if you want to race in a standard class. regs need the 8/32.
inspection required after 10hrs racing and its not to be used for any races longer than 12hrs. replacement depends on inspection results. 8/32 is recommended to be replaced after 8000km with regular inspections.
the GT3R/RS ran the same 1,2 and 3 as the cup but then had a shorter 4th, longer 5th and longer 6th.

not quite sure the porsche motorsport dept in weissach have hillclimbs on their schedule board, though i accept that this would be a good use for it (though perhaps not the car).


Edited by fioran0 on Saturday 18th February 11:35

keep it lit

3,388 posts

167 months

Saturday 18th February 2012
quotequote all
7:35 was for rallying.

mrdemon

21,146 posts

265 months

Saturday 18th February 2012
quotequote all
the issue you have is a base 997 911 with a power pack can match a GT3/RS to 100mph and beat it to 60mph.

997.1 GT3 ratios are too long for a road car imo.
3rd gear takes you past 110MPh !!!



Edited by mrdemon on Saturday 18th February 12:24

fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
ade smile

mrdemon......FFS. is your car leaking some NOS into the cabin?

nsm3

2,831 posts

196 months

Saturday 18th February 2012
quotequote all
mrdemon said:
the issue you have is a base 997 911 with a power pack can match a GT3/RS to 100mph and beat it to 60mph.

997.1 GT3 ratios are too long for a raod car imo.
3rd gear takes you pass 110MPh !!!
silly

mrdemon

21,146 posts

265 months

Saturday 18th February 2012
quotequote all
I don't need NOS my cars already faster than any GT3 :-p

joking aside, :-p

A 997.1 C2s power pack car is faster to 60mph and just about to 100mph than a 997.1 GT3 or RS.

Imo the 997.1 GT3 ratio's are way to long for a road car, don't you agree ?

nsm3

2,831 posts

196 months

Saturday 18th February 2012
quotequote all
No

mrdemon

21,146 posts

265 months

Saturday 18th February 2012
quotequote all
nsm3 said:
No
well Porsche did because in the 997.2 GT3 they shortened them.

I don't think most people even know what they have lol

Edited by mrdemon on Saturday 18th February 12:26

nsm3

2,831 posts

196 months

Saturday 18th February 2012
quotequote all
Did you notice any difference when you compared the two sets of ratios?

ttdan

1,091 posts

193 months

Saturday 18th February 2012
quotequote all
mrdemon said:
nsm3 said:
No
well Porsche did because in the 997.2 GT3 they shortened them.

I don't think most people even know what they have lol

Edited by mrdemon on Saturday 18th February 12:26
shortened only on the RS, not the regular GT3

fioran0

Original Poster:

2,410 posts

172 months

Saturday 18th February 2012
quotequote all
Too long for a road car, no.
They could do with being closer together and shorter for track driving, something Porsche has been creeping towards as increased rev ranges offset some of the road compromise this brings. A lot of folks run 8/32 final drive to change this.

0-60 times mean nothing unless you drag strip.




Steve Rance

5,446 posts

231 months

Saturday 18th February 2012
quotequote all
fioran0 said:
the 8/32 (4.0) final drive change is applied as a percentage drop to each gear so has the effect of very slightly closing the gear spacing as larger speeds are reduced more than lower ones. it mainly just lowers the speed across the board though. the cup has completely different ratios fitted to keep the spacing shorter between gears.
with an 8/32 fitted you get:
6.1GT3......1st-34mph,...2nd-63mph,...3rd-83mph,...4th-106mph,...5th-133mph,...6th-157mph
6.2GT3......1st-34mph,...2nd-63mph,...3rd-83mph,...4th-106mph,...5th-130mph,...6th-152mph

changing to an 8/32 on the street boxes helps shorten things down so that 4,5 and 6 can be brought into use easier but at the expense of a much shortened 1,2 and 3.

Edited by fioran0 on Saturday 18th February 11:26
Yep I think that a cup final drive is a really usable and cost effective upgrade to a 996gt3. Maybe pound for pound one of the best.

mrdemon

21,146 posts

265 months

Saturday 18th February 2012
quotequote all
fioran0 said:
Too long for a road car, no.
They could do with being closer together and shorter for track driving, something Porsche has been creeping towards as increased rev ranges offset some of the road compromise this brings. A lot of folks run 8/32 final drive to change this.
if they are to long for track work they are way to long for B road driving.

Good for the ring though lol